In conventional order-picking systems, individual picking orders are frequently received and processed over the day. Some orders can be picked immediately after the receipt. Other orders may not yet have come in, but will be received in the course of the day. In this case, it may also happen that a customer, such as a retail subsidiary, transmits a number of orders on the same day respectively having different content. In this case, the problem is that goods which are to be sent, for example, to the same subsidiary, need to be stored over a certain period of time in order to keep the number of delivery trips as low as possible. It is a problem on principle to accumulate deliveries and prepare the same for a loading process.
In order to solve this problem, so-called “accumulation tracks” have been proposed in the prior art for accumulating goods of one single order, or of one single subsidiary (in some cases a sum of a number of orders). Such accumulation tracks are exemplarily described in the European patent EP 1 542 916 B1. These accumulation tracks typically are very long, allowing accumulating all goods, which are determined for one track, one after the other and side-by-side. The document EP 1 542 916 B1 discloses a method for keeping gaps between individual goods of an order as small as possible, in order to pack the to-be-accumulated goods as dense as possible. Nevertheless, a lot of space is required for allowing building correspondingly long accumulation tracks in a shipping area of the order-picking system. As a rule, a number of orders (track loads) are handled in parallel by arranging a number of accumulation tracks side-by-side (in a horizontal plane).
Additional conveyors and loading devices are described in the documents DE 38 30 692 A1, U.S. Pat. No. 3,974,888 A, DE 10 2004 001 181 A. EP 438 667 A2, EP 447 104 A2 and DE 195 18 298 A1.
Another problem caused by the preparation of different goods is to be seen in the loading or unloading sequence of the goods. In particular, retail subsidiaries typically wish to have an unloading sequence for the ordered goods, since the ordered goods are loaded directly from the truck into the racks of the subsidiary. Thus, a lot of customers pre-determine the unloading sequence, which is expressed in terms of a mirrored loading sequence. However, if different articles of an order are handled at different times within the order-picking system, provision of a so-called “sorter”, (i.e. a sorting device) is necessarily required, the sorter being arranged upstream relative to the shipping area including the plurality of accumulation tracks. A conveyor circle is an exemplary sorter, which is arranged between a warehouse and order-picking area and a shipping area including several destinations or shipping locations. Goods can circle within the circle for a longer time until the article, which is required next in the accumulation track (shipping location) in accordance with a predetermined loading or unloading sequence, is introduced into the circle. This is disadvantageous in that a relatively space-consuming unit (conveyor circle in terms of a sorter) is used. On the other hand, a significant computing expenditure at the end of a superordinated controlling device (material flow computer) can be caused, in particular if the orders are processed in parallel, in order to manage the goods of the different orders simultaneously, in particular when mixing and subsequently separating the same.